dsRNAi-mediated silencing of PIAS2beta specifically kills anaplastic carcinomas by mitotic catastrophe.

The E3 SUMO ligase PIAS2 is expressed at high levels in differentiated papillary thyroid carcinomas but at low levels in anaplastic thyroid carcinomas (ATC), an undifferentiated cancer with high mortality. We show here that depletion of the PIAS2 beta isoform with a transcribed double-stranded RNA-directed RNA interference (PIAS2b-dsRNAi) specifically inhibits growth of ATC cell lines and patient primary cultures in vitro and of orthotopic patient-derived xenografts (oPDX) in vivo. Critically, PIAS2b-dsRNAi does not affect growth of normal or non-anaplastic thyroid tumor cultures (differentiated carcinoma, benign lesions) or cell lines.

RET signalling provides tumorigenic mechanism and tissue specificity for AIP-related somatotrophinomas.

It is unclear how loss-of-function germline mutations in the widely-expressed co-chaperone AIP, result in young-onset growth hormone secreting pituitary tumours. The RET receptor, uniquely co-expressed in somatotrophs with PIT1, induces apoptosis when unliganded, while RET supports cell survival when it is bound to its ligand. We demonstrate that at the plasma membrane, AIP is required to form a complex with monomeric-intracellular-RET, caspase-3 and PKCδ resulting in PIT1/CDKN2A-ARF/p53-apoptosis pathway activation.

GFRα 1-2-3-4 co-receptors for RET Are co-expressed in Pituitary Stem Cells but Individually Retained in Some Adenopituitary Cells.

The RET tyrosine kinase receptor is expressed by the endocrine somatotroph cells of the pituitary where it has important functions regulating survival/apoptosis. However, RET is also expressed by the GPS pituitary stem cells localized in a niche between the adenopituitary and the intermediate lobe. To bind any of its four ligands, RET needs one of four co-receptors called GFRα1-4.

Unmasking a new prognostic marker and therapeutic target from the GDNF-RET/PIT1/p14ARF/p53 pathway in acromegaly.

Background: Acromegaly is produced by excess growth hormone secreted by a pituitary adenoma of somatotroph cells (ACRO). First-line therapy, surgery and adjuvant therapy with somatostatin analogs, fails in 25% of patients. There is no predictive factor of resistance to therapy.

Rewiring of the apoptotic TGF-β-SMAD/NFκB pathway through an oncogenic function of p27 in human papillary thyroid cancer.

Papillary thyroid carcinoma (PTC), the most frequent thyroid cancer, is characterized by low proliferation but no apoptosis, presenting frequent lymph-node metastasis. Papillary thyroid carcinoma overexpress transforming growth factor-beta (TGF-β). In human cells, TGF-β has two opposing actions: antitumoral through pro-apoptotic and cytostatic activities, and pro-tumoral promoting growth and metastasis.

Humanized medium (h7H) allows long-term primary follicular thyroid cultures from human normal thyroid, benign neoplasm, and cancer.

Context: Mechanisms of thyroid physiology and cancer are principally studied in follicular cell lines. However, human thyroid cancer lines were found to be heavily contaminated by other sources, and only one supposedly normal-thyroid cell line, immortalized with SV40 antigen, is available. In primary culture, human follicular cultures lose their phenotype after passage.